The defiant 24-year Capitol Hill Democrat has had a perennial target on his back for conservatives — even though Peterson votes against his own party nearly a third of the time. His Seventh Congressional District spans most of western Minnesota, from the Canadian border nearly down to Iowa. Voters there lean more red than blue, which has long fanned Republican hopes that they can persuade voters to dump Peterson for one of their own.

So far, no luck.

Last year, the man who ran against Peterson, state Sen. Torrey Westrom, raised more than $1 million and got help from the national party. Peterson defeated him by nearly 10 points, spending $1.5 million on the race and winning 54 percent of ballots cast.

Peterson’s popularity has proved durable for one reason. In this sprawling district that is home to 22,000 square miles of prime farmland and nearly 50,000 farm operators, voters see Peterson as someone who will defend agriculture interests — no matter the politics or the cost to taxpayers.

“We could lose the family farm. … We fight every day to keep that,” Peterson said, speaking at a recent Summit on Rural America in Washington, D.C. He said a lot of new lawmakers “have no idea what goes on in rural America, they have no idea what it takes to grow food. We have a challenge trying to educate people.”

Democrats have learned to live with Peterson’s regular defections. Their bigger worry is that he will eventually retire.

At 70, Peterson is edging closer to the time when he will trade in long travel days to Washington and constant rounds of fundraising for time on his farm near Thief River Falls, and hanging out with his 94-year-old father. But that’s for later. Peterson is still eager to protect a legacy that he sees as increasingly embattled.

The fragile 2014 farm bill agreement, which Peterson likes to note garnered support from both GOP House Speaker John Boehner and Democratic Minority Leader Nancy Pelosi, was tendered after the two sides agreed on funding both the food stamp program and agriculture subsidies.

That kind of compromise works, Peterson said, because both sides get to go back to voters with something.

“These folks who talk about the need to split this up, you want to make sure there’s not a farm bill? That is a strategy that will work 100 percent,” he said.

The 2014 farm bill is costing a few billion more dollars than previous agreements because of a combination of new programs for farmers and some market downturns for crops like sugar. University of Missouri researchers estimate that there will be more than $24 billion in payments to farmers from 2014 to 2018 — a $2.4 billion increase from the previous four-year period.

These steeper costs may make it increasingly hard for a deeply divided Congress, particularly in the most conservative U.S. House of Representatives in years, to hammer out future deals, Peterson said.

“It’s going to be very tough,” he said, in his speech to rural community leaders.

Republicans say he remains among their top targets nationally, though they do not yet have a candidate to run against him next year. “Collin Peterson has split with the Farm Bureau on two high-profile votes … leaving Minnesota farmers out to dry,” reads a National Republican Congressional Committee spin e-mail.

To that, Peterson grunts: “Whatever.”

One of those votes was on labeling requirements for beef, pork and chicken. Peterson led the push to keep requirements in place because he said Americans deserve to know where their meat comes from. The American Farm Bureau, and many Republicans, opposed it because the nation’s two biggest trading partners, Canada and Mexico, threatened to retaliate through tariffs if the requirements were left in place. Peterson ultimately lost the fight on the House floor.

Minnesota Farm Bureau President Kevin Paap says he understands.

“There is no greater champion in agriculture,” Paap said. “We understand we do things sometimes and maybe he will vote a different way.”

Peterson had talked about retiring in 2014, but he said he decided to run again because the acrimonious campaign the Republicans ran against him made him so mad.

Minnesota regulators reaffirmed their support Monday for Enbridge Energy's proposal to replace its aging Line 3 crude oil pipeline across northern Minnesota, while dozens of protesters walked out of the overflow hearing to make a point about climate change.